Heat exchange device



July 18, 1950 J,B WALLER 2,515,750

HEAT EXCHANGE DEVICE Filed Sept. 6, 1946 2 SheetsSheet l flV/E-A/fafil M055 5 MILLER July 18, 1950 J. B. WALLER 2,515,750

HEAT EXCHANGE DEVICE Filed Sept. 6, 1946 2 Sheets-Sheet 2 U U I 2x /5' if! 24 22 M9 9 w /Z n v. /Z

m/VE/V ae doazw/ Z5. M24452 Patented July 18, 1950 v UNITED STATES PTENT OFFICE HEAT EXCHANGE DEVICE 3 Joseph B. Waller, Baltimore, Md. Application September 6, 1946, Serial No. 695,137

This invention relates to a heat exchange device and comprehends more particularly the regulation of temperature in the cooling'chamber of arefrigerating unit or similar unit having a separate compartment for the coolant.

It is primarily the object of my invention to provide a cooling unit with novel means for conducting and regulating the exchange of heat between a cooled compartment and a coolant.

Another object of this invention is to provide a cooling unit of the above character provided with a manual control which sets the temperature desired and an automatic control which maintains the icebox substantially at that temperature.

-Still another object of this invention is the provision of a portable refrigerating container of durable construction, having a separate Dry Ice or other coolant chamber contained therein and which has a channelized heat transfer system from the coolant chamber to the rest of the container in order that the internal temperature of the unit may be more readily controlled and maintained within desired limits, and at the same time the full efficiency of the coolant ob tained.

With these and other objects in view, the invention broadly embraces incorporating with a refrigerating unit a novel heat exchange device which has both automatic and manual controls. The cooling effect is accomplished by heat being conducted from a contact surface in the cooling compartment through a heat conducting path to a surface in contact with a coolant, substantially all heat exchange taking place through said path. The heat contact surfaces are joined by a transverse conductive path which conducts heat from one of said surfaces to the other. Both manual and automatic means are provided for regulating the cross sectional area of the conductive path to thereby regulate the rate at which heat is exchanged from one contact surface to the other.

The above objects and other objects I accomplish by a combination and arrangement of parts of which I show a preferred embodiment in the accompanying drawings.

Referring to the drawings in which the same or similar reference numerals apply to identical parts:

Figure l is a top plan view, partly broken away, showing a portable refrigerating unit embodying the present invention.

Figure 2 is a side elevational view, partly in central transverse section, of the refrigerating unit shown in Figure 1. l

*8 Claims. (01. 62-129) Figure 3 is a vertical sectional view of the heat exchange device taken along the line 3-3 of Figure 2.

Figure 4 is a horizontal sectional view taken along the line 4-4 of Figure 2 in which the insulation has been omitted to clarify the disclosure.

Figure 5 is a transverse view taken along the line 5-5 of Figure 4.

Referring more particularly to the drawings, Figure 1 shows a portable refrigerating unit I, with a cooling chamber 2, and compartment for a coolant 3. The unit is enclosed by insulation material 4 and the chamber 2 is thermally iso-- lated from the compartment 3 by substantially heavy walls of insulation 5.

A heat transfer device, indicated generally as 6 and composed of a material having high heat conducting properties such as copper interconnects the compartment 3 and the chamber 2 through the insulating wall 5. This heat transfer device, as best seen in Figures 2 and 3 comprises a contact plate or surface I which occupies a horizontal position substantially covering thebottom of the compartment 3. A second plate or heat absorbing surface 8 is positioned in the chamber 2 and is connected with the plate I through the insulating wall 5 by means of a conducting element indicated generally as 9.

In accordance with the invention, the element 9 provides a heat conducting path of variable cross sectional area between the plates 1 and 8 and to accomplish this, the element 9 comprises a platelike member H! which forms a continuous, permanent connection between the plates 1 and 8. As seen in Figure 3, one end ll of the member 9 is attached, such as by screws to the plate 1. This edge is continuous across the upper end of member 9 and provides a substantial surface contact with the plate 1 while the opposite end of the member 9 is bifurcated, tapering to a pair of substantially narrow tips l2 which are connected such as by means of screws to the plate 8 and provide a surface contact o the member 9 therewith appreciably less than with the plate I.

ment 9 and, as a consequence, the heat conducting capacity of the path formed thereby is increased or decreased as the strips l3 and I5 are in contact or parted. Moreover by virtue of the reduced cross sectional area of the permanent portion of the path afiorded by the narrow tips [2, the degree of variability in heat conductivity and resulting heat transfer is increased.

To provide for automatic control of the heat conducting capacity of the connecting path between the plates 1 and 8 in order to maintain the temperature in the chamber 2 within desiredlimits of temperature range, the followingmeche anism is provided:

A round rod I'l journaled on the outerside wall. of refrigerating unit I has knob [8 attached for.

manual rotation. This rod passes through the insulated wall of unit I and then throughilower insulated portion of compartment 3 perpendicular to..the plane of the conducting path: 9-. Itterminatesagainst a rotatable disc, lfljournaled in a cup 29 positioned on an outer side wallof com.- partment. 3. whichisexposed to the atmosphere ofeh'amben 2..

Concentricto the rod I I. is a square shaft2l which extends almost the total length of therod...

Whereshaitilcrosses .theplane of the conducting path 9 it is linked by meansof .a crank 22.to the. middleot. a crossbar 23. which is. pivotally attachedjateach; end 24 to the movable stripslfi which'aretlius moved, inparallel relation,.to an equaliextent with respect to fixed strips l3.

O'neend ofLsh'aft 2! extends into cup-.2!) on the outside of compartment 3'where itis securedito. the free end of a bimetallic,-thermostatZEii thermostat is fixedly clamped. to disc l9 by, means ofclamps 2t.

Temperature changes in chamber 2 cause only the free end of.thermstat 25.to move, thus r0- tatingshaft 2| and making and breaking contact between strips l3 and I5 through the linkage comprisingcrank 22 and crossbar 23. However, by manually turning knob. l8, rod. I! will rotate disc lfi'which in turn will move the thermostat 25in'toto and.c.onsequently actuate shaft 2| to make or.break contact between strips I3 and I5. Thus the coolingaction ofjthe refrigeratingunit can. be changed atany given moment. In addition, the manualcontrol obtained through knob l8fenables the'setting'of temperature-range limits through. which the thermostatic control is effected. Frictional engagement between the inside wall of cup and the fiat-surface of disc IS-firmly holds the thermostat in the position as setby the knob l3, so that all movement of the iii-metallic strips istransmitted, only through shaft 2!. may be such that either a great or a small tem-- perature change is required to make contact'betwe'en strips 3 and I5. But once the desired temperature range is reachedv the thermostat automatically holds-the coolingchamber within that temperature range by alternately making and breaking contact between strips l3 and i5 to increase and decrease the cross sectional area of the conductive path, as the temperature inchamber Z'moves first to one limit'and then to the other of" the predetermined temperature range;

Mention should'be made of the fact'that plate 8= does':not haveeto be a solid plate. It may be a foraminous plate or even a coil. By coil is meant not-a fluid bearing-coil but something in the nature-oif'acoarse rod: or a pipe which mayhave cooling finson it;

It is apparent from the foregoing'that the re- This In" other words, the manual settingfrigerating unit works on a variable heat exchange principle of a new and improved character. The narrowing down of the permanent connections of the heat conducting path between the contact surfaces permits a definitely appreciable control of the temperature of the cooling compartment by action of the movable connections which make and break contact. As a result of manual setting; or a thermostatic setting cooperating with the manual setting, the cooling medium is thus efficiently used and not wasted by dissipation when not required. Furthermore, goods storedmay be held substantially at desired temperatures.

While. only one embodiment of the invention has been..described, it is to be understood that such a heatexchange principle could readily be applied to large refrigeration units, refrigerating cars, cold storage rooms or even buildings, or any other refrigeration. unit of, whatever. sort, .nature, or. description.

Iclaimz.

l. Ina heat exchange device, acooling chamher, a compartment. for. containing a coolant; means forming a permanent metallic heat COIT- ducting. path between. said compartment" and. chamber, said. means includingat least-oneipair of'separable metallic members adapted-to con-'- tact each other to. form a secondheat conducting path between said, compartment and said chamher, and means ch'angesofsaid chamber for making and breaking contact between said members.

In a heat exchange device, a cooling'cham her, a compartment for containing a coolant, means including at least one pair of separable metallic members adapted to contact each other to' form .aheat conducting path between said compartment and chamber, one of said pair of members-beingfixed in position and the other" member being movable, a thermostat within said chamber; means operatively connecting the thermostat'to the 'movable'metallic member for mak ing and breaking'eontact between saidfixed and movable members in response to temperature changes within said chamber, a manually controlled member to move'the thermostat, and said movable member to set temperature limitswithirr which-the thermostat will be effective in making and breaking contact" between the separable members;

3. In a heat exchange device, a cooling'chamher, a compartment for containing a coolant; means including at least one pair of separable. metallic. members adapted to contaet each other;

to.form..a heat conducting. path between said;

compartment andchamber, one of. each ofsaid members being fixed in position andv the..other. member being; movable, athermostat, a member; connecting the thermostat to the said movable. metallic member, in. order to make and break; contact between said fixed and movable memebers-in. response. to temperature..-changes within said chamber, a manually controlled member; linked tothemovablemetallic member in :orderto make or break contact between the said, sep, arable members andgthuschange the cross. sectional. areabf' the heat conducting path.

4. In a heat exchange device, a cooling charm-e her; a. compartment for containing a"v coolant, a contact surface in said chamber, a contact surface in said compartment, a. permanent; metallic heat conductingpath between said: contact :surfaces making several times greater area: contact with one of the surfacesthan with the responsive to temperature" other, at least one pair of separable members comprising fixed and movable metal strips adapted to cont-act each other to form an additional heat conducting path between said contact surfaces, a rotatable shaft, link means connecting the shaft to the movable strip for moving the same to make and break contact with the fixed strip, and thermostatic means for rotating the shaft.

5. In a heat exchange device, a cooling chamber, compartment for containing a coolant, a contact surface in said chamber, a contact surface in said compartment, a permanent metallic heat conducting path between said contact surfaces making several times greater area contact with one of the surfaces than with the other, at least one pair of separable members comprising fixed and movable metal strips adapted to contact each other to form an additional heat conducting path between said contact surfaces, a rotatable shaft linked to said movable metal strip and secured to the free end of a bimetallic thermostat, said thermostat being fixed on a surface which rotates through the action of a manual control.

6. In a heat exchange device, an insulated cooling chamber, an insulated compartment for containing a coolant, a contact surface placed horizontally in the bottom of said chamber, a contact surface in said compartment, a permanent metallic heat conducting path extending through the insulation between said surfaces making several times greater area contact with one of said surfaces than with the other, at least one pair of separable metallic members comprising fixed and movable metal strips adapted to contact each other to increase the cross sectional area of the heat conducting path, a rotatable shaft linked to said movable metal strip and secured to the free ends of a bimetallic thermostat, said thermostat being fixed to a 6 surface which rotates through the action of a manually controlled rod passing longitudinally through the center of the said rotatable shaft.

7. In a heat exchanging device, a cooling chamber, a compartment for a refrigerant, a heat conducting element in the cooling chamber for receiving heat from the chamber, a heat conducting element in the refrigerant compartment, a metallic sheet permanently connecting the elements, a second metallic sheet joining the elements, and means to disconnect the second metallic sheet responsive to the temperature in the chamber to control the rate of heat transfer between the elements.

8. A heat exchanging device comprising a cooling chamber, a compartment for a refrigerant, a heat conducting plate in the chamber, a heat conducting :plate in the compartment, a metallic sheet extending between the heat conducting plates to transfer heat from one of the plates to the other, said sheet having a large area in engagement with one of the plates and a small area in engagement with the other plate, metallic strips pivotally contacting the sheet adapted to move into and out of heat transfer relationship With the heat conducting plate having a small area of contact with the metallic sheet in response to temperature changes in the chamber.

JOSEPH B. WALLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,901,000 Robe Mar. 14, 1933 1,927,168 Goosman Sept. 19, 1933 1,980,089 Rice Nov. 6, 1934 2,043,190 Carpenter June 2, 1936 2,300,529 Smith Nov. 3, 1942 

